1. Field of the Invention
The present invention relates to a substrate processing apparatus that performs a predetermined process of substrates such as semiconductor substrates, glass substrates for liquid crystal display devices, and glass substrates for photomasks, and to a substrate processing method.
2. Description of the Background Art
Conventionally, known in the manufacturing steps of substrates is a substrate processing apparatus that performs a process such as a cleaning process of the substrates within a chamber. For example, there is known a substrate processing apparatus in which a chemical solution is stored in a cleaning bath disposed within the chamber, and a cleaning process is carried out by immersing substrates in the chemical solution.
Such a substrate processing apparatus is placed and used at various locations. Consequently, the atmosphere around the substrate processing apparatus is not always constant. For example, the atmosphere around the substrate processing apparatus when placed at a low location differs from that when placed at a high location. The atmosphere around the substrate processing apparatus may also vary according to the weather and the setting of a clean room in a factory.
A change in the atmosphere around the substrate processing apparatus changes the pressure within the chamber unless the pressure is specially controlled. If the pressure within the chamber is controlled, only by a relative pressure control of the chamber on the basis of ambient atmosphere, a change in the ambient atmosphere may change the pressure within the chamber. It is therefore difficult for the conventional substrate processing apparatus to maintain the pressure within the chamber constant irrespective of location environment.
Additionally, when the pressure within the chamber is controlled in the conventional substrate processing apparatus, the whole of the chamber including a processing part is subjected to pressure control. Nevertheless, the pressure control covering the whole of the chamber has poor efficiency of pressure control because the chamber further includes a region other than the processing part.